lecture_3_302k - Motion under constant acceleration(written...

Outline of Lecture #3 30-August-2010 Rob Clark 1. Definition of some terms (book Sec. 2.1-2.4) a. A particle is an object whose size can be neglected in a given problem. b. Position is the coordinate of a particle along some axis. c. Displacement is a difference between two positions; it can be positive or negative. d. Distance is the absolute value of displacement; it is always positive. e. Average velocity is the displacement that occurs over some time interval divided by the time interval. f. Instantaneous velocity is the velocity of a particle at one moment in time. It is found by taking the limit as the time interval becomes very small. g. Instantaneous acceleration and average acceleration are defined analogously to instantaneous and average velocity, but they are a difference in velocities, rather than positions, divided by some time interval. 2. Motion under constant acceleration (book Sec. 2.5)

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Unformatted text preview: Motion under constant acceleration (written a) can be exactly solved for the velocity and position of a particle at any point in time. We take the initial time to be t = 0. The velocity is given by v = v + a t, where v 0 is the initial velocity and t is the time. The position is given by x = x + v 0 t + (1/2) a t 2 , where x is the initial position. Using the definitions of average velocity and the equation for v vs. t, you can derive other relations for motion under constant acceleration: x- x 0 = (1/2) (v + v) t v 2 = v 2 + 2 a (x-x ) You can learn all these formulas separately, but I recommend deriving them from each other. The ones I choose to remember are the first two, which give the velocity and position in powers of the time. Please re-read these sections if anything is not clear. These are concepts that will be used throughout the entire course....
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